Bioacoustics of Thanatus elongatus

Diagnosis. Thanatus elongatus is characterised by the specific configuration of tibial apophyses and bulbal sclerites of the male palp ( Figs 2A–B , 3A–B ) and the female genitalic structures ( Figs 2C–H , 3C–D ). Currently it cannot be allocated to a particular species group. The male resembles those of some Asian species, above all T. hongkong Song, Zhu & Wu, 1997 , T. pollex Li, Feng & Yang, 2012 , T. fornicatus Simon, 1897 , and T. mongolicus ( Schenkel, 1936 ) . It can be separated from T. hongkong by the G-shaped sperm duct loop (S-shaped in T. hongkong ), from T. pollex by the compact RTA (elongated and tapering RTA in T. pollex ), from T. fornicatus by the short VTA (VTA longer than RTA in T. fornicatus ) and from T. mongolicus by the robust embolus tip (filiform ventrad tip in T. mongolicus ). The epigyne of Thanatus elongatus resembles those of Thanatus fornicatus Simon, 1897 and Thanatus saraevi Ponomarev, 2007 , but the vulva is strikingly different: glandular heads situated mediolaterally (anterolateral in both T. fornicatus and T. saraevi ); spermathecae almost spherical and separated from each other (with tubular elongation posteriorly and relatively closer to each other in both T. fornicatus and T. saraevi ) (cf. Figs 2A–H , 3A–D with figs 3–8 in Logunov 2011 , figs 11–12 in Levy 1991 , figs 2B–C in Li et al . 2012 , figs 2A–B in Song et al . 1997 , and figs 8, 13, 24, 35 in Kastrygina & Kovblyuk 2013 ). Justification of transfer. Tikader (1960) described Tibellus elongatus on the basis of a single female specimen collected from Calcutta (now Kolkata). Detailed examination of the holotype , additional specimens from Calcutta and newly collected material including both sexes from South India , show that this species has diagnostic features of Thanatus : oval to elongate body; eyes small, of almost same size; anterior row of eyes distinctly closer together than posterior row of eyes ( Figs 1G–H ); both eye rows moderately recurved, with the posterior row of eyes almost equally spaced ( Figs 1G–H ); legs relatively long; abdomen oval, slightly tapering posteriorly, dorsomedially with dark longitudinal marking ( Figs 1A, D–E ); male palp with simple RTA and VTA; embolus distally on tegulum; epigynum with broad median septum; spermathecae with glandular head ( Levy 1977 ). Based on the presence of all of these characters, the species is thus transferred to Thanatus .